1. Field of the Invention
The present invention relates to a lens driver unit comprising a retractable lens barrel, and an imaging device and a hand-held data terminal device including the same.
2. Description of the Related Art
Recently, in the field of an imaging device such as a digital camera, high-performance optical systems have been developed and downsizing of the imaging device has been in progress in accordance with users' increasing demands. In such a situation, there has been a demand for an imaging device to comprise a retractable type optical system in which a lens barrel is retracted into an inside of a device body during non-use for imaging a subject. Moreover, to satisfy users' demands for downsizing a camera body or the like, it is very important to decrease the size of a movable barrel portion in an optical axis direction in a retracted state as much as possible.
In order to satisfy such a demand for downsizing a camera body, Japanese Patent No. 3771909 discloses a lens barrel which comprises a plurality of lens frames holding a plurality of lens groups respectively, a movable lens barrel containing the lens frames, and a frame driver moving the lens frames via the lens barrel, to move, to a subject side, at least part of the plurality of lens groups in a contained state in which at least part of them are retracted in a camera body so that the lens groups are to be ready for imaging a subject. Such a lens barrel is configured to include a retreat lens frame which has all the respective lens groups positioned on the optical axis in the imaging state while holding at least one of the lens groups to move it to a position away from the optical axis in the contained state. According to this lens barrel, since in the contained state a part of the lens groups are retreated outside an original storage space for the movable lens barrel, it is possible to reduce the size of the lens barrel in the optical axis direction and downsize a camera body.
However, such a lens barrel has a problem in increasing the size thereof in the contained state and increasing component costs when the number of lens groups movable along the optical axis is increased. In other words, this makes it difficult to improve lens performance without increases in costs and size and limits the freedom of lens design.